Trial conducted by Novartis to evaluate safety and efficacy of Albuferon
administered every four weeks in combination with ribavirin in patients with
genotypes 2 and 3 hepatitis C

Rockville, MD -- January 12, 2009 -- Human Genome Sciences, Inc. (Nasdaq:
HGSI) today announced that Novartis has initiated dosing in a Phase 2b trial
that will evaluate the safety and efficacy of Albuferon (albinterferon
alfa-2b) administered monthly in combination with ribavirin in
treatment-naive patients with genotypes 2 and 3 chronic hepatitis C.
Albuferon is being developed by HGS and Novartis under an exclusive
worldwide co-development and commercialization agreement entered into in
June 2006.

"Patients undergoing treatment for chronic hepatitis C often find it
challenging to participate in normal daily activities, especially in the
days following dose administration," said Stephen Pianko, MD, FRACP, PhD,
Monash University, Melbourne, Australia. "Pegylated interferons, the current
standard of care, require administration once every week. Albinterferon
alfa-2b dosed every four weeks with a total of six injections could offer an
important treatment option, if it demonstrates comparable safety and
efficacy vs. peginterferon alfa-2a dosed weekly with a total of 24
injections."

In December 2008, HGS announced that Albuferon met its primary endpoint of
non-inferiority to peginterferon alfa-2a (Pegasys) in ACHIEVE 2/3, a Phase 3
clinical trial of Albuferon in combination with ribavirin in treatment-naive
patients with genotypes 2 and 3 chronic hepatitis C. In these patients, the
Phase 3 study showed that 900-mcg Albuferon administered every two weeks had
efficacy comparable to peginterferon alfa-2a [Pegasys], with comparable
rates of severe and/or serious adverse events and discontinuations due to
adverse events.

"Hepatitis C is the most common chronic blood-borne infection in the
developed world, and there continues to be a significant need for more
effective and better tolerated treatments," said Mani Subramanian, MD, PhD,
Executive Director, Clinical Research - Infectious Diseases, HGS. "Only an
estimated 40% of U.S. patients diagnosed with chronic hepatitis C have
undertaken treatment to date - in part due to the side effects associated
with interferon injections, which are currently required on a weekly basis.
A monthly dosing schedule with Albuferon may well result in more patients
choosing to be treated."

About the Design of the Phase 2b Monthly Dosing Trial

This Phase 2b trial is a randomized, open-label, multi-center,
active-controlled, adaptive-design dose-ranging study to evaluate the safety
and efficacy of albinterferon alfa-2b administered every four weeks plus
daily ribavirin in treatment-naive patients with genotypes 2 and 3 chronic
hepatitis C. Approximately 375 patients will be randomized in a 4:4:4:3
ratio into four treatment groups, including three that will receive
albinterferon alfa-2b administered once every four weeks (900 mcg, 1200 mcg
or 1500 mcg), in addition to the active-control group, which will receive
peginterferon alfa-2a at the standard 180-mcg dose once every week. All
patients in the study will receive 800-mg daily oral ribavirin. The total
duration of treatment will be 24 weeks. The primary efficacy endpoint is
sustained virologic response (SVR) at Week 48 (24 weeks following the end of
treatment).

About Albinterferon Alfa-2b (Albuferon)

Albinterferon alfa-2b is a novel, longer-acting form of interferon alfa that
was created using the proprietary HGS albumin-fusion technology. Human
albumin is the most prevalent naturally occurring blood protein in the human
circulatory system, persisting in circulation in the body for approximately
19 days. Research has shown that genetic fusion of therapeutic proteins to
human albumin decreases clearance and prolongs the half-life of the
therapeutic proteins. Albuferon results from the genetic fusion of human
albumin and interferon alfa.

Albuferon is being developed by HGS and Novartis for the treatment of
chronic hepatitis C under an exclusive worldwide co-development and
commercialization agreement entered into in June 2006. HGS and Novartis will
co-commercialize Albuferon in the United States and will share clinical
development costs, U.S. commercialization costs and U.S. profits equally.
Novartis will be responsible for commercialization in the rest of the world
and will pay HGS a royalty on those sales. Clinical development, commercial
milestone and other payments to HGS could total as much as $507.5 million,
including $132.5 million received to date.